English grammar

The English grammars here presented target the Corpus500, and are provided as a didactic sample that may help users to build their own grammars. They are used for representing the English sentences into UNL (UNLization) and for generating English sentences from UNL graphs (NLization). They follow the syntax defined at the UNL Grammar Specs and have been used for IAN and EUGENE.

Requisites

The grammars here presented depend heavily on the structure of the dictionary presented at English dictionary. You have to be acquainted with the formalism described at the UNL Dictionary Specs and the Tagset in order to fully understand how the grammar deal with the dictionary entry structure. You should also understand the process of tokenization done by the machine.

Features

The grammars play with a set of features that come from three different origins:

• Dictionary features are the features ascribed to the entries in the dictionary, and appear either as simple attributes (LEX,GEN,NUM), as simple values (N,MCL,SNG) or attribute-value pairs (LEX=N,GEN=MCL,NUM=SNG).
• System-defined features are features automatically assigned by EUGENE and IAN during the processing. They are the following:
  • SHEAD = beggining of the sentence (system-defined feature assigned automatically by the machine)
  • CHEAD = beginning of a scope (system-defined feature assigned automatically by the machine)
  • STAIL = end of the sentence (system-defined feature assigned automatically by the machine)
  • CTAIL = end of a scope (system-defined feature assigned automatically by the machine)
  • TEMP = temporary entry (system-defined feature assigned to the strings that are not present in the dictionary)
• Grammar features are features created inside the grammar in any of its intermediate states between the input and the output.

All the features are described at the Tagset.